"It's probably the biggest thing I've ever done besides American Idol," Phillips told the AP. "I'm just excited to get out there and do my first real live performance since everything that's been going on."

It has been a rough few months for the Leesburg, Ga. Native, who suffers from a congenital kidney stone problem. In March, the 21-year-old singer received emergency medical treatment for pain in his abdomen prior to the Top 13 results show. In late May, Phillips' father, Phillip Phillips Sr., revealed that his son had eight operations during American Idol's run.

Most recently, Phillips underwent another surgery in early June to remove kidney stones that were too large to pass.

"I'm getting better each day, so that's a good thing. I'm just walking around, getting my strength back together," he said. "It was tough, you know, those first few days, but I'm getting to where I can pick the guitar back up and write a little bit."

When Phillips takes the stage on July 4, he'll join Matthew Broderick, Megan Hilty, U.S. Olympic athletes and other celebrities at the concert. It is set to broadcast live on PBS and NPR.